For those that go a few weeks between washing and get the brake dust really stuck to the plastic cladding.
Was washing my truck yesterday and was having a heck of a time getting the brake dust off areas of the front wheels. Had an idea, ran in and grabbed my wife's Mr. Clean Extra Power Magic Eraser. The wheels came spotless with little to no effort at all.
Don't know if it will work on other types of wheels but mine look like brand new. Super cheap only like 2 or 3 dollars in the super market.